Medical devices used to treat and diagnose patients may come into contact with internal or external areas of the patients, creating a risk of transmitting bacteria, viruses, or other infectious diseases from one patient to another. Sterilization, or the elimination of all transmissible agents (including bacteria, viruses, and other microorganisms), of medical devices, is used to prevent spreading diseases between patients who are treated or diagnosed with the same medical devices.
Methods for sterilizing medical devices are commonly carried out in a device called an autoclave and are performed by using heat, radiation, or chemicals. Heat sterilization exposes a medical device to pressurized steam to sufficiently heat the surfaces of the device to effect sterilization. In order to be effective, the steam needs to impinge all surfaces, thus limiting the size of the item being sterilized by the size of the autoclave. While one of the most widely used methods of sterilization, not all medical devices, or not all parts of a medical device, can survive the requisite temperatures and pressures used in heat sterilization. For example, electrical components and/or particular materials comprising a portion of the medical device may be damaged by the application of such sterilizing steam.
Radiation sterilization exposes all surfaces of a medical device to ionizing radiation, such as gamma radiation, x rays, or high-energy electrons, in order to create charged particles and free radicals within the transmissible agents. The charged particles and free radicals act to damage the inner workings of the agent (such as a bacteria's DNA), thereby killing the agent after enough damage has accumulated. While effective, radiation sterilization requires the use of expensive equipment to handle the source of the ionizing radiation. The size of apparatus for containing and safely delivering such radiation is limited, thus limiting the size of the item being sterilized. Moreover, not all medical devices, or not all parts of a medical device, can survive exposure to such radiation. For example, electrical components and/or particular materials comprising a portion of the medical device may be damaged by the application of such sterilizing radiation.
Chemical sterilization exposes all surfaces of a medical device to chemical compounds, such as ethylene oxide gas or liquid glutaraldehyde, with known sterilizing properties for a fixed amount of time to effect sterilization. While chemical sterilization enables low temperature sterilization without the use of radioactivity, its use is still limited in that the chemical compounds used are toxic and expensive. Not all medical devices, or not all parts of a medical device, can survive exposure to such chemicals. For example, electrical components and/or particular materials comprising a portion of the medical device may be damaged by the application of such sterilizing chemicals.
Ultrasound devices are used by the medical industry to provide images of the muscle and soft tissue of patients. Ultrasound devices may be used in noninvasive procedures, such as during pregnancy to image the developing fetus, or may be used in invasive procedures, such as during surgery to image internal tissue and organs of the patient. Ultrasound devices typically comprise a base unit and a scan head. The base unit is operable to control the scan head, interpret the ultrasonic pulses, and generate the image of the tissue of the patient and typically does not come into contact with any portion of the patient, preventing the need for sterilization. The scan head is generally comprised of an ultrasonic transducer and a cable wherein the cable is sufficiently long to prevent the patient from coming into contact with or otherwise contaminating the base unit. In some configurations, the ultrasound device may provide a connection between the base unit and the ultrasonic transducer, such as to allow the use of differently configured transducers, to allow for their replacement, etc. In operation, the scan head is placed onto or inside of the patient and sends and receives ultrasonic pulses, thus necessitating sterilization.
Generally, a scan head may require sterilization where the base unit may does not. Accordingly, the use of a connector detachably connecting the scan head to the base unit allows the scan head to be separated from and sterilized apart from the base unit, such that the base unit does not need to be designed to withstand sterilization. However, portions of the scan head assembly may not be suitable for exposure the sterilization process. For example, the connector itself may be damaged by the sterilization process. Additionally, the connector of the scan head may contain delicate electrical components that need to be protected from sterilization. However, when used on a patient for imaging, only portions of the of the scan head (the transducer and possibly some portions of the cable) come into contact with the patient. While some portions (the transducer and cable) of the scan head necessitate sterilization, other portions (the connector) need to be protected from sterilization. Protective enclosures that surround the connector are used to protect it from sterilization while still allowing the transducer and cable of the scan head to be sterilized.
The types and sizes of medical devices to be sterilized in an autoclave or other sterilization apparatus are limited by the size of the sterilization apparatus. Yet, a protective enclosure must be large enough to contain, seal, and adequately protect portions of the medical device from sterilization. Prior art protective enclosures for use with scan head assemblies have generally been relatively large, e.g., protecting the entire connector by providing an enclosure fully incarcerating the scan head assembly connector and providing a seal through which the cable to the transducer passes. Such a configuration suffers from disadvantages such as an enclosure which is too large to fit into many sterilization apparatus. Additionally, by closing the seal against the cable, such prior art enclosures may cut into or otherwise damage the cable after repeated sterilizations. Further, as the connector is not held in place within the enclosure, the connector may become damaged by forcefully contacting the enclosure when the scan head is being handled or sterilized.